Abstract

TiO2 was employed as an additional support by physical mixing with the WO3/SiO2 catalysts and used in the metathesis of ethylene and trans-2-butene for propylene production. Having nano-sized TiO2 as the additional support could enhance trans-2-butene conversion and propylene yield. The results suggested that tungsten could migrate from an original support and form more well-dispersed surface tetrahedral tungsten oxide species on the additional support, leading to a better dispersion. It was also shown that TiO2 having nano size could provide better spreading of the tungsten species than the micro size. A smaller crystallite size evidenced from XRD and a higher ratio between surface tetrahedral tungsten oxide species over crystalline WO3 evidenced from FT-Raman spectra of the nano-sized TiO2 systems were, among other things, advantageous to metathesis activity improvement of the catalyst. This study offers a guidance of supplementing the existing catalysts as one simple way of improvement in the catalytic performances which can easily be applied in the real metathesis reaction process.

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Acknowledgments

The authors would like to thank the financial supports from Chulalongkorn University, the Thailand Research Fund (TRF), the Office of Higher Education Commission, and the NRU-CU (AM-1088D). The special thanks also go to the Ratchadaphiseksomphot Endowment Fund of Chulalongkorn University (RES560530021-CC). The Royal Golden Jubilee Ph.D. scholarship from TRF and SCG Chemicals for W.L. are also gratefully acknowledged.